/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */

int maxDepth(struct TreeNode* root){
    if(NULL == root)
        return 0;
    int leftHegiht = maxDepth(root->left);
	int rightHegiht = maxDepth(root->right);

	return leftHegiht > rightHegiht ? leftHegiht+1 : rightHegiht+1;

}